iio: ak8975 : Add AK8963 compatibility mode support

AK8963 and AK8975 use same register definitions, except the range of X,Y,Z values. Added support of 8963 based on i2c_device_id. Unfortunately there is no way to detect the type via registers, both device registers return 0x48 as id of chipset. Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: ak8975 : Add AK8963 compatibility mode support
AK8963 and AK8975 use same register definitions, except the range of X,Y,Z values. Added support of 8963 based on i2c_device_id. Unfortunately there is no way to detect the type via registers, both device registers return 0x48 as id of chipset. Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Srinivas Pandruvada · Jonathan Cameron
1 parent 239670ef48
Showing 2 changed files with 31 additions and 6 deletions Side-by-side Diff
drivers/iio/magnetometer/Kconfig
drivers/iio/magnetometer/ak8975.c
@@ -11,7 +11,8 @@
 	depends on GPIOLIB
 	help
 	  Say yes here to build support for Asahi Kasei AK8975 3-Axis
-	  Magnetometer.
+	  Magnetometer. This driver can also support AK8963, if i2c
+	  device name is identified as ak8963.
  
 	  To compile this driver as a module, choose M here: the module
 	  will be called ak8975.
@@ -85,8 +85,15 @@
 #define AK8975_MAX_CONVERSION_TIMEOUT	500
 #define AK8975_CONVERSION_DONE_POLL_TIME 10
 #define AK8975_DATA_READY_TIMEOUT	((100*HZ)/1000)
-#define RAW_TO_GAUSS(asa) ((((asa) + 128) * 3000) / 256)
+#define RAW_TO_GAUSS_8975(asa) ((((asa) + 128) * 3000) / 256)
+#define RAW_TO_GAUSS_8963(asa) ((((asa) + 128) * 6000) / 256)
  
+/* Compatible Asahi Kasei Compass parts */
+enum asahi_compass_chipset {
+	AK8975,
+	AK8963,
+};
+
 /*
  * Per-instance context data for the device.
  */
@@ -101,6 +108,7 @@
 	int			eoc_irq;
 	wait_queue_head_t	data_ready_queue;
 	unsigned long		flags;
+	enum asahi_compass_chipset chipset;
 };
  
 static const int ak8975_index_to_reg[] = {
@@ -272,9 +280,21 @@
  * Since ASA doesn't change, we cache the resultant scale factor into the
  * device context in ak8975_setup().
  */
-	data->raw_to_gauss[0] = RAW_TO_GAUSS(data->asa[0]);
-	data->raw_to_gauss[1] = RAW_TO_GAUSS(data->asa[1]);
-	data->raw_to_gauss[2] = RAW_TO_GAUSS(data->asa[2]);
+	if (data->chipset == AK8963) {
+		/*
+		 * H range is +-8190 and magnetometer range is +-4912.
+		 * So HuT using the above explanation for 8975,
+		 * 4912/8190 = ~ 6/10.
+		 * So the Hadj should use 6/10 instead of 3/10.
+		 */
+		data->raw_to_gauss[0] = RAW_TO_GAUSS_8963(data->asa[0]);
+		data->raw_to_gauss[1] = RAW_TO_GAUSS_8963(data->asa[1]);
+		data->raw_to_gauss[2] = RAW_TO_GAUSS_8963(data->asa[2]);
+	} else {
+		data->raw_to_gauss[0] = RAW_TO_GAUSS_8975(data->asa[0]);
+		data->raw_to_gauss[1] = RAW_TO_GAUSS_8975(data->asa[1]);
+		data->raw_to_gauss[2] = RAW_TO_GAUSS_8975(data->asa[2]);
+	}
  
 	return 0;
 }
@@ -499,6 +519,9 @@
 	data->eoc_gpio = eoc_gpio;
 	data->eoc_irq = 0;
  
+	data->chipset = (enum asahi_compass_chipset)(id->driver_data);
+	dev_dbg(&client->dev, "Asahi compass chip %s\n", id->name);
+
 	/* Perform some basic start-of-day setup of the device. */
 	err = ak8975_setup(client);
 	if (err < 0) {
@@ -552,7 +575,8 @@
 }
  
 static const struct i2c_device_id ak8975_id[] = {
-	{"ak8975", 0},
+	{"ak8975", AK8975},
+	{"ak8963", AK8963},
 	{}
 };
...	...	@@ -11,7 +11,8 @@
11	11	depends on GPIOLIB
12	12	help
13	13	Say yes here to build support for Asahi Kasei AK8975 3-Axis
14		- Magnetometer.
	14	+ Magnetometer. This driver can also support AK8963, if i2c
	15	+ device name is identified as ak8963.
15	16
16	17	To compile this driver as a module, choose M here: the module
17	18	will be called ak8975.
...	...	@@ -85,8 +85,15 @@
85	85	#define AK8975_MAX_CONVERSION_TIMEOUT 500
86	86	#define AK8975_CONVERSION_DONE_POLL_TIME 10
87	87	#define AK8975_DATA_READY_TIMEOUT ((100*HZ)/1000)
88		-#define RAW_TO_GAUSS(asa) ((((asa) + 128) * 3000) / 256)
	88	+#define RAW_TO_GAUSS_8975(asa) ((((asa) + 128) * 3000) / 256)
	89	+#define RAW_TO_GAUSS_8963(asa) ((((asa) + 128) * 6000) / 256)
89	90
	91	+/* Compatible Asahi Kasei Compass parts */
	92	+enum asahi_compass_chipset {
	93	+ AK8975,
	94	+ AK8963,
	95	+};
	96	+
90	97	/*
91	98	* Per-instance context data for the device.
92	99	*/
...	...	@@ -101,6 +108,7 @@
101	108	int eoc_irq;
102	109	wait_queue_head_t data_ready_queue;
103	110	unsigned long flags;
	111	+ enum asahi_compass_chipset chipset;
104	112	};
105	113
106	114	static const int ak8975_index_to_reg[] = {
...	...	@@ -272,9 +280,21 @@
272	280	* Since ASA doesn't change, we cache the resultant scale factor into the
273	281	* device context in ak8975_setup().
274	282	*/
275		- data->raw_to_gauss[0] = RAW_TO_GAUSS(data->asa[0]);
276		- data->raw_to_gauss[1] = RAW_TO_GAUSS(data->asa[1]);
277		- data->raw_to_gauss[2] = RAW_TO_GAUSS(data->asa[2]);
	283	+ if (data->chipset == AK8963) {
	284	+ /*
	285	+ * H range is +-8190 and magnetometer range is +-4912.
	286	+ * So HuT using the above explanation for 8975,
	287	+ * 4912/8190 = ~ 6/10.
	288	+ * So the Hadj should use 6/10 instead of 3/10.
	289	+ */
	290	+ data->raw_to_gauss[0] = RAW_TO_GAUSS_8963(data->asa[0]);
	291	+ data->raw_to_gauss[1] = RAW_TO_GAUSS_8963(data->asa[1]);
	292	+ data->raw_to_gauss[2] = RAW_TO_GAUSS_8963(data->asa[2]);
	293	+ } else {
	294	+ data->raw_to_gauss[0] = RAW_TO_GAUSS_8975(data->asa[0]);
	295	+ data->raw_to_gauss[1] = RAW_TO_GAUSS_8975(data->asa[1]);
	296	+ data->raw_to_gauss[2] = RAW_TO_GAUSS_8975(data->asa[2]);
	297	+ }
278	298
279	299	return 0;
280	300	}
...	...	@@ -499,6 +519,9 @@
499	519	data->eoc_gpio = eoc_gpio;
500	520	data->eoc_irq = 0;
501	521
	522	+ data->chipset = (enum asahi_compass_chipset)(id->driver_data);
	523	+ dev_dbg(&client->dev, "Asahi compass chip %s\n", id->name);
	524	+
502	525	/* Perform some basic start-of-day setup of the device. */
503	526	err = ak8975_setup(client);
504	527	if (err < 0) {
...	...	@@ -552,7 +575,8 @@
552	575	}
553	576
554	577	static const struct i2c_device_id ak8975_id[] = {
555		- {"ak8975", 0},
	578	+ {"ak8975", AK8975},
	579	+ {"ak8963", AK8963},
556	580	{}
557	581	};
558	582